1. Field of the Invention
The present invention relates to a hard coat film used for producing a radiation image conversion panel, and the radiation image conversion panel obtained by using the hard coat film.
2. Description of the Related Art
In recent years, display devices such as a liquid crystal display and a touch panel display have rapidly become widespread. On a surface of such display devices, a film in which a hard coat material is used as a protective layer is disposed. Above all, the liquid crystal display is noticeably getting larger and larger and is used for various purposes. Therefore, the hard coat material used for such a liquid crystal display is expected to have higher hardness, than those used for other displays, and to have smaller film curls during curing. Further, the hard coat material herein is also expected to have higher adhesiveness to a base material.
To solve the above-mentioned problems, for example, JP 2011-190343 A (Kyoeisha Chemical Co., Ltd.) discloses, as a hard coat composition, a composition including (A) a urethane(meth)acrylate resin, (B) a multifunctional (meth)acrylate resin, (C) a (meth)acrylate-containing fluorine compound, and (D) a metal-oxide microparticle. However, there is a case where the above-mentioned hard coat composition does not have sufficient adhesiveness to the base material with respect to a strong repetitive sliding or an impact.
Further, in a digital radiation image detecting device typified by a computed radiography (CR), a flat panel type radiation detector (FPD) and the like, a radiation image conversion panel including a phosphor layer is used. Examples of such a radiation image conversion panel include one that is used for a method in which fluorescence emitted from the phosphor layer is directly detected by a photoelectric conversion element to provide an image. Further, such examples include one that is used for a method in which the phosphor layer accumulates some radiation energy, and is irradiated with excitation light such as visible light. Herein, photostimulated luminescence which occurs in accordance with the accumulated energy is detected to provide an image.
On the other hand, the phosphor-containing phosphor layer is sensitive to mechanical alteration such as damages due to friction, and chemical alteration such as deliquescence due to moisture in the air and the like. Such alteration may easily cause deterioration in the quality of the radiation image.
Accordingly, as a method using the radiation image detecting device, a radiation image conversion panel used with a configuration in which a protective layer is disposed on a phosphor layer has been known. However, in such a radiation image conversion panel in the related art, a surface of the protective layer repetitively comes into contact with a surface of other objects depending on its use. As a result, scratches easily appear on the surface of the protective layer. The scratches herein cause deterioration in the radiation image eventually obtained, or cause deterioration in the quality of image information relating to the radiation image. Therefore, improvement in a damage-proof property of the protective layer has been further demanded.
To solve the above-mentioned problems, for example, JP 8-190000 A (FUJIFILM Corporation) discloses a radiation image conversion panel including a protective layer that includes a transparent base material and a resin composition layer, containing a fluorinated resin, disposed thereon.
However, a coated film including the fluorinated resin disclosed in JP 8-190000 A may not necessarily obtain sufficient hardness. Further, there is a case where the coated film may not obtain sufficient scratch resistance with respect to the repetitive sliding due to minute inorganic materials such as sand. To overcome such weaknesses, JP 2001-133598 A (FUJIFILM Corporation) discloses a protective layer in which a hard coat layer having pencil hardness of 2H or more is applied to a transparent base material. Although the protective layer herein has high scratch resistance, adhesiveness of the hard coat layer to the transparent base material is not sufficient. Therefore, there is a possibility that a phenomenon occurs in which the hard coat layer and the transparent base material come off with respect to the repetitive sliding due to the minute inorganic material such as sand or the impact.